Changes in the security situation facing citizens in the United States and military personnel abroad have greatly increased the threat that chemical weapons will be used against American forces and American civilians in the field as well as at home. In addition, hundreds of thousands of Americans are exposed to significant levels of pesticide organophosphates (OP) every year. These situations point to an urgent need for an efficient, fieldable and inexpensive way to detect OP. Detection instrumentation is an essential component of any protection paradigm, and thus a challenge is to develop sensitive and inexpensive detection methodology for various OP agents. The goal of our work is to be able to detect biomarkers of OP nerve agent exposure that can be readily and inexpensively deployed using a portable automated multianalyte biosensor. Our long-term goals are to develop a sensitive biosensor to detect biomarkers of OP exposure to provide information to protect populations at risk for exposure to chemical warfare agents or OP pesticides. The Aims for this research include: Aim 1) Design and synthesize biomarker reagents for a system to detect nerve agents including tabun, sarin, soman, VX, GF and tabun;Aim 2) Prepare and test antibodies to biomarkers of nerve agent exposure;Aim 3) Obtain biological samples from animals exposed to nerve agents or their surrogates;Aim 4) Develop the biosensor for nerve agent exposure and Aim 5) Build and test the final biosensor. Biochemical validation and development of a robust, portable Array Biosensor employing the optimized reagents and using currently available technology will be done in collaboration with the Naval Research Laboratory. With the success of the proposed work, we will obtain: 1) new reagents and technology for identifying OP-biomolecule conjugates of relevance to nerve agent and pesticide OP exposure, 2) verification of the robustness of the technology with biological samples, 3) development of an array-based methodology to selectively detect OP and 4) elaboration and testing of an Array Biosensor in the field with biological samples taken from animals exposed to low doses of nerve agents or nerve agent analogs. The final sensitive and selective product will be of use in a rapid screening format of physiological fluids for OP exposure.